Early redox activities modulate Xenopus tail regeneration.

Redox state sustained by reactive oxygen species (ROS) is crucial for regeneration; however, the interplay between oxygen (O2), ROS and hypoxia-inducible factors (HIF) remains elusive. Here we observe, using an optic-based probe (optrode), an elevated and steady O2 influx immediately upon amputation. The spatiotemporal O2 influx profile correlates with the regeneration of Xenopus laevis tadpole tails. Inhibition of ROS production but not ROS scavenging decreases O2 influx. Inhibition of HIF-1α impairs regeneration and stabilization of HIF-1α induces regeneration in the refractory period. In the regeneration bud, hypoxia correlates with O2 influx, ROS production, and HIF-1α stabilization that modulate regeneration. Further analyses reveal that heat shock protein 90 is a putative downstream target of HIF-1α while electric current reversal is a de facto downstream target of HIF-1α. Collectively, the results show a mechanism for regeneration via the orchestration of O2 influx, ROS production, and HIF-1α stabilization

The role of post-translational modifications on STAT3 interactions

"The JAK/STAT3 pathway is involved in multiple biological phenomena, mostly related to stress or tissue damage, but also development and cancer. A rate-limiting step of the pathway involves STAT3 dimerization, phosphorylation and translocation to the nucleus. Originally, it was thought that STAT3 dimerized upon phosphorylation by JAKs on Y705. However, current evidence indicates that STAT3 exists as a dimer prior to phosphorylation and activation, and that phosphorylation only induces a change in the conformation of the dimer.(...)"N/

Unifying the low-temperature photoluminescence spectra of carbon nanotubes: the role of acoustic phonon confinement

At low temperature the photoluminescence of single-wall carbon nanotubes show a large variety of spectral profiles ranging from ultra narrow lines in suspended nanotubes to broad and asymmetrical line-shapes that puzzle the current interpretation in terms of exciton-phonon coupling. Here, we present a complete set of photoluminescence profiles in matrix embedded nanotubes including unprecedented narrow emission lines. We demonstrate that the diversity of the low-temperature luminescence profiles in nanotubes originates in tiny modifications of their low-energy acoustic phonon modes. When low energy modes are locally suppressed, a sharp photoluminescence line as narrow as 0.7 meV is restored. Furthermore, multi-peak luminescence profiles with specific temperature dependence show the presence of confined phonon modes

EOLES Course, 4 years and going…results and experiences

The EOLES (Electronics and Optics e-Learning for Embedded Systems) course consists of a 3rd year Bachelor degree that relies exclusively on e-learning and remote laboratories, developed as the result of an EU funded ERASMUS+ project, involving 15 institutions from four European and three North African countries and concluded in 2015. The developed course was accredited as a specialization year in most partner institutions and has been running non-stop since then, mainly with students from North African institutions. Although no longer supported by an EU project, the course is a good example of sustainability as it already had 4 effective editions with successful approval rates and always with many more candidates than available vacancies. This paper presents an overview and overall results for this initial period and a more detailed analysis of the Digital Systems Teaching Unit. The focus is on the course specific characteristics and features, student and teacher experiences and the methodologies that were applied to enhance learning results. Although being a fully online course, several synchronous activities and communication tools are included in the methodology to enhance student and teacher iteration and also to provide an impartial grading process, as required for accreditation. The course expositive material is provided as the student progresses, with progressive unlocking of content depending on each teaching unit timeline, and automatic quizzes results. In short, students are allowed and encouraged to adjust their learning rhythm within the limits allowed by time restraints and evaluation criteria.info:eu-repo/semantics/publishedVersio

EOLES Course, 4 years and going…results and experiences

The EOLES (Electronics and Optics e-Learning for Embedded Systems) course consists of a 3rd year Bachelor degree that relies exclusively on e-learning and remote laboratories, developed as the result of an EU funded ERASMUS+ project, involving 15 institutions from four European and three North African countries and concluded in 2015. The developed course was accredited as a specialization year in most partner institutions and has been running non-stop since then, mainly with students from North African institutions. Although no longer supported by an EU project, the course is a good example of sustainability as it already had 4 effective editions with successful approval rates and always with many more candidates than available vacancies. This paper presents an overview and overall results for this initial period and a more detailed analysis of the Digital Systems Teaching Unit. The focus is on the course specific characteristics and features, student and teacher experiences and the methodologies that were applied to enhance learning results. Although being a fully online course, several synchronous activities and communication tools are included in the methodology to enhance student and teacher iteration and also to provide an impartial grading process, as required for accreditation. The course expositive material is provided as the student progresses, with progressive unlocking of content depending on each teaching unit timeline, and automatic quizzes results. In short, students are allowed and encouraged to adjust their learning rhythm within the limits allowed by time restraints and evaluation criteria.info:eu-repo/semantics/publishedVersio

Giant optical anisotropy in a single InAs quantum dot in a very dilute quantum-dot ensemble

We present the experimental evidence of giant optical anisotropy in single InAs quantum dots. Polarization-resolved photoluminescence spectroscopy reveals a linear polarization ratio with huge fluctuations, from one quantum dot to another, in sign and in magnitude with absolute values up to 82%. Systematic measurements on hundreds of quantum dots coming from two different laboratories demonstrate that the giant optical anisotropy is an intrinsic feature of dilute quantum-dot arrays.Comment: submitted to Applied Physics Letter

Dephasing processes in a single semiconductor quantum dot

International audienceWe discuss the decoherence dynamics in a single semiconductor quantum dot and analyze two dephasing mech- anisms. In the ¯rst part of the review, we examine the intrinsic source of dephasing provided by the coupling to acoustic phonons. We show that the non-perturbative reaction of the lattice to the interband optical transition results in a composite optical spectrum with a central zero-phonon line and lateral side-bands. In fact, these acoustic phonon side-bands completely dominate the quantum dot optical response at room temperature. In the second part of the paper, we focus on the extrinsic dephasing mechanism of spectral di®usion that determines the quantum dot decoherence at low temperatures. We interpret the variations of both width and shape of the zero- phonon line as due to the °uctuating electrostatic environment. In particular, we demonstrate the existence of a motional narrowing regime in the limit of low incident power or low temperature, thus revealing an unconventional phenomenology compared to nuclear magnetic resonance

E-Engineering: from concept to reality

Even before the digital era, the implementation of distance learning in higher education was a reality in many areas. Notwithstanding, the offer of distance higher education courses was not equal in all knowledge areas due to different teaching and learning requirements. The experimental work developed during the learning process in engineering areas is widely recognized as essential for engineering students. However, the remote availableness of this experimental, hands-on, works, typically done in University laboratories designed according to the different teaching subject requirements, was nonexistent. With the advent of remote laboratories, real-time remotely controlled laboratory facilities made possible by the advancements on the Internet network, this limitation disappeared. The concept of e-engineering, a merge between the e-learning concept and the remote laboratories, emerged as a solution to offer distance learning engineering courses without abdicating of the indispensable practical component of any engineering course. Two European projects – the Tempus EOLES project and the ERASMUS+ e-LIVES project – try to bridge the gap between concept and reality by first implementing an accredited higher education engineering course in Electronics and Optics e-Learning for Embedded Systems and then by producing a set of guidelines to help others to be autonomous in the creation of their own eengineering courses.info:eu-repo/semantics/publishedVersio

Cognitive and Emotional Alterations Are Related to Hippocampal Inflammation in a Mouse Model of Metabolic Syndrome

Converging clinical data suggest that peripheral inflammation is likely involved in the pathogenesis of the neuropsychiatric symptoms associated with metabolic syndrome (MetS). However, the question arises as to whether the increased prevalence of behavioral alterations in MetS is also associated with central inflammation, i.e. cytokine activation, in brain areas particularly involved in controlling behavior. To answer this question, we measured in a mouse model of MetS, namely the diabetic and obese db/db mice, and in their healthy db/+ littermates emotional behaviors and memory performances, as well as plasma levels and brain expression (hippocampus; hypothalamus) of inflammatory cytokines. Our results shows that db/db mice displayed increased anxiety-like behaviors in the open-field and the elevated plus-maze (i.e. reduced percent of time spent in anxiogenic areas of each device), but not depressive-like behaviors as assessed by immobility time in the forced swim and tail suspension tests. Moreover, db/db mice displayed impaired spatial recognition memory (hippocampus-dependent task), but unaltered object recognition memory (hippocampus-independent task). In agreement with the well-established role of the hippocampus in anxiety-like behavior and spatial memory, behavioral alterations of db/db mice were associated with increased inflammatory cytokines (interleukin-1β, tumor necrosis factor-α and interleukin-6) and reduced expression of brain-derived neurotrophic factor (BDNF) in the hippocampus but not the hypothalamus. These results strongly point to interactions between cytokines and central processes involving the hippocampus as important contributing factor to the behavioral alterations of db/db mice. These findings may prove valuable for introducing novel approaches to treat neuropsychiatric complications associated with MetS